The present invention is concerned with resource management such as network radio resource management in wireless networks.
In recent years multimedia delivery over the Internet has sharply increased becoming the main bandwidth consumer within the network. Parallel to this increase, significant improvements in mobile networks have led to the apparition of high speed access networks such as 3GPP's High Speed Downlink Packet Access (HSDPA) and the emerging Long Term Evolution (LTE) networks.
With the improvements in mobile networks IP services are expected to be a ubiquitous fact of the daily life. Recent studies expect that consumption of multimedia content, especially video streaming, is going to continue increasing [1], which may also be a result of the advances in mobile networks. In fact, in [2] it has been reported that about the 50% of the data traffic in mobile networks is video data and it is expected that two-thirds of the world's mobile data traffic will be video by 2015.
HTTP streaming is one of the promising multimedia applications that has emerged in the last years and has had an incredible acceptance by the market, which is evident by the standardization activities on adaptive HTTP streaming carried out by different standardization bodies, such as MPEG [3] and 3GPP [4] or proprietary solutions such as IIS Smooth Streaming [5] and HTTP Live Streaming [6].
Although media streaming has been associated previously with RTP/UDP due to its lower latency, relying on HTTP/TCP for media delivery has shown to be a very valuable solution for scenarios where extremely stringent delay constraints are not considered, since traversal problems within NAT and Firewalls, typical with RTP/UDP, are not present.
Dynamic Adaptive Streaming over HTTP (DASH) [3] is an emerging MPEG standard, which defines a format for multimedia delivery over HTTP. It basically consists of two elements: the format of the media to be downloaded and the description of the media to be downloaded. Existing proprietary solutions are based on a similar approach.
The media format is basically structured in typically small time intervals of video, called segments, which if continuously downloaded allow for a continuous representation of the media. Furthermore, usually different representations, e.g. encodings, of the media at different bitrates are available at the server allowing for a user-driven adaptation, where users select representations based on the observed network throughput. Download of segments of different representations for different time intervals is allowed resulting in a perfectly playable media, if all switching constraints presented in the Media Presentation Description (MPD), described below, are followed.
In DASH, the description of the format is given by the MPD. The MPD is an XML document, which describes the data and especially the segments available at the server. Using the MPD the clients have the information necessitated to make the requests which fit their network throughput or their requirements.
In DASH the clients are responsible for performing adaptation. Based on the interests of the users, equipment capabilities and current status of the network, DASH clients have to select the representation(s) described in the MPD, which match best the necessities/capabilities of the clients. An example of DASH architecture is shown in FIG. 1.
As is visible from FIG. 1, the participating entities in a DASH environment are: the DASH server 10 which receives its media content to be distributed to respective DASH clients 12 from some DASH content preparation stage 14, the DASH client 12 itself and the network interconnecting the DASH server 10 and the DASH client 12 with the network 16 being denoted as “HTTP Cache”. As depicted in FIG. 3, the DASH client may run on a suitable user terminal such as a television device or a computer or the like, when the DASH client receives from the DASH server 10 the media presentation description MPD 18 which, in turn, has been generated along with the versions of the media content by the DASH content preparation stage 14 so as to describe the various versions of the media content available at the DASH server 10.
FIG. 2 shows the state of the art of the deployment architecture of DASH in LTE networks which uses entities from the DASH standard [ISO/IEC 23009-1]. The white boxes specify the DASH system, while the shaded boxes specify the LTE system. To be more precise, in transferring the DASH infrastructure to LTE networks, the DASH client 12 is shown to be connected to the HTTP CASH 16 via a concatenation of an LTE base station 20, a radio channel 22 and a user entity 24, wherein a radio resource manager 26 is shown to be comprised by the base station 20 and the user entity 24 may be a mobile terminal such as a mobile phone or the like at which the DASH client 12 is operating in form of, for example, a software running on the user entity's processor. It is assumed that the DASH client 12 as well as the LTE eNB 20 have access to the media presentation description (MPD 18). The MPD 18 provides sufficient information about the video representation at server 10 to provide a streaming service to the user 12 by the user requesting segments from the HTTP server 10 using TCP/IP as transport protocol. Initially, the dash client 12 transmits a HTTP get request to the HTTP server 10. After HTTP handshake a TCP tunnel between server 10 and client 12 is established. This TCP tunnel is transparent for the underlying physical transport layer. Depending on the information provided by the MPD 18, the DASH client 12 has enough information for demultiplexing, decoding and rendering the included media data appropriately.
The problem involved with the scenario depicted in FIG. 2 is the usual behavior of the DASH client 12 according to which each DASH client 12 seeks to provide its user with the version of the media content residing on the respective server 10 having the highest quality and/or information content possible at the currently assigned communication resources, assigned by the radio resource manager 26 to the user entity 24 of the respective DASH client 12. The “highest possible” quality/information content could then one having maximum spatial resolution, maximum number of views, maximum width depth and the like, thereby necessitating the highest bandwidth. This, in turn, means that each DASH client 12 maximally strains the available radio resources of the base station 26 and the base station and the radio resource manager 26, respectively, has to cope with steadily requesting an increase of assigned communication resources in order to obtain one of the available higher level versions of the media content which the respective DASH client of the respective user entity wishes to obtain. Naturally, this leads to a suboptimal distribution of the radio communication resources to the user entities which distribution or scheduling is performed based on a current channel situation and user profiles assigned to the individual user entities 24.
Accordingly, it is an object of the present invention to provide a resource management concept which enables a more efficient use of the available communication resources in order to, for example, maximize the number of satisfied users.